With the popularization of intelligent mobile terminals and rapid development of mobile applications, scenarios in which users use mobile data increase greatly in number. As a result, it becomes increasingly difficult for existing networks to satisfy requirements of increasing mobile data traffic. Generally, a wireless cellular network has advantages such as wide coverage and support for high-speed movement but also has disadvantages such as a low data transmission rate, a high price, and high transmission power. A wireless local area network (WLAN) has advantages such as a high data transmission rate, a low price, and low transmission power but also has disadvantages such as small coverage.
To satisfy requirements of increasing mobile data traffic, a wireless cellular network technology and a WLAN technology are integrated in the prior art, and a WLAN is used to offload data traffic from a wireless cellular network, to improve user experience and implement efficient and cost-efficient communication. Currently, the 3rd Generation Partnership Project (3GPP) provides a Long Term Evolution-wireless local area network aggregation (LWA) technology. A general packet radio service tunnelling protocol-user plane (GTP-U) tunnel can be established between a base station and a wireless local area network termination (WT). The GTP-U tunnel is used to transmit data, to implement integration of the wireless cellular network technology and the WLAN technology and implement a WLAN offloading technology.
However, only downlink data can be transmitted in the existing LWA technology. When user equipment (UE) needs to send uplink data, offloaded data cannot be transmitted to the base station by using the GTP-U tunnel established between the base station and the WT.